Washington (CNN) - A point of Ticker privilege here as we say goodbye to CNN Photojournalist Mike Greene, who retires Friday.

Greene has covered the White House for CNN since the first Bush administration – more than 20 years. In fact, he covered President Ronald Reagan before joining the ranks at CNN. That's five presidents.
What was one of his most memorable moments? Shooting the visit of South African President Nelson Mandela and President Bill Clinton to the prison cell where the leader had spent so many years incarcerated.

Before Thursday's White House briefing, the White House press corps took a moment to honor one of its own.